Field
An aspect of the present invention relates to a DC-DC converter and an organic light emitting display device using the same, and more particularly, to a DC-DC converter and an organic light emitting display device using the same which has optimal efficiency by adaptively operating according to a load condition.
Description of the Related Art
Among flat panel display devices, an organic light emitting display device displays images using organic light emitting diodes (OLEDs) that emit light through recombination of electrons and holes. The OLED includes an anode electrode, a cathode electrode and a light emitting layer positioned between the anode and cathode electrodes. If current flows through the OLED in the direction from the anode electrode to the cathode electrode, the OLED emits light, thereby expressing a color. In the organic light emitting display device, emission luminance is determined according to the amount of current flowing through the OLED of each pixel. Therefore, a high-luminance image requires more driving current than a low-luminance image. That is, the driving current required to drive pixels of the organic light emitting display device is changed depending on a displayed image. Accordingly, in order to reduce power consumption, a DC-DC converter for driving the pixels of the organic light emitting display device should be designed to have high efficiency throughout the entire range of the driving current. However, the switching frequency of a related art DC-DC converter is fixed to a frequency at which DC-DC conversion can be normally performed under the maximum load condition, and therefore, the efficiency is degraded as the load decreases.